Could Amanda Knox be Extradited to Italy?

Today's ruling by Italy's Supreme Court ordering a new murder trial for Amanda Knox guarantees the legal drama will drag on for several more years and will be expensive.

It also raises the possibility that if Knox is found guilty and that verdict is upheld by Italy's Supreme Court, Knox could eventually face a request to extradite her and put her back in prison.

An extradition request would likely turn on whether being prosecuted again after being exonerated constitutes double jeopardy.

Knox and her ex-boyfriend Raffaele Sollecito were convicted in 2009 after a lengthy and controversial trial for the murder of her British roommate Meredith Kercher in 2007. Knox was sentenced to 26 years in prison while Sollecito got 25.

That verdict was tossed out in 2011 by an appeals court that blasted the prosecution's handling of critical DNA evidence and the case in general.

Knox had hoped today's Supreme Court ruling would uphold her innocence and put an end to her six year ordeal. Instead she was "shocked" when the court ordered the appeals court to retry the case.

Knox, 25, now faces years of legal maneuvering and hearings starting when the case is expected to go back to trial early next year.

Knox, who has already spent four years in an Italian prison, does not intend to return to Italy for the proceedings, possibly putting her lawyers at a disadvantage. She won't be able to testify on her own behalf and she won't be able to take advantage of Italy's right of "spontaneous declarations" in which the defendant can stand and make a statement to defend herself against particular testimony.

Her absence at the new trial could prompt the appellate court to declare her in contempt of court, but that carries no additional penalties.

The outcome of the retrial is certain to be appealed to the Supreme Court by whichever side loses.

If Knox is again convicted and the verdict is upheld by the Supreme Court, Italy would be expected to seek her extradition in order to put her back in prison.

"We've got a [extradition] treaty," said Bruce Zagaris, a Washington-based attorney who specializes in extradition cases. "The Senate has already ratified that treaty and decided that Italy is a country with which we ought to have a treaty. They wouldn't have ratified if they didn't think the Italian process was fair and due process was sufficient."

"She can try to fight extradition, but it will be an uphill battle," Zagaris said.

In the American legal world being retried for the same crime sounds like "double jeopardy," a principle in the U.S. judicial system and enshrined in the Constitution that outlaws being tried twice for the same crime.

American unease with double jeopardy could give Knox a "fighting chance" to appeal any extradition in a U.S. court, said Christopher L. Blakesley, a professor of international law University of Nevada Las Vegas.

"There's room to fight extradition," Blakesley said, "and double jeopardy is the spot to fight on…. In the treaty, we functionally accept their system of justice, but it's up to a magistrate to decide whether" the double jeopardy clause of the Constitution was violated and if that trumps the treaty.

Asked about Knox's prospects for extradition, a State Department spokesman said "we never talk about extradition from the podium," during the daily briefing for reporters, and said the U.S. would wait for the final explanation from the Italian Supreme Court before commenting.